#include <stdio.h>  
char ans[105][30];  
  
void sum(int x) {  
    int temp = 0, temp2 = 0;  
    for (int i = 0; i < 29; i++) {  
        ans[x][i] = temp;  
        temp = temp + ans[x - 1][i] - '0' + ans[x - 2][i] - '0' > 9 ? 1 : 0;  
        if (temp == 1)  
            ans[x][i] += ans[x - 1][i] - '0' + ans[x - 2][i] - 10;  
        else  
            ans[x][i] += ans[x - 1][i] - '0' + ans[x - 2][i];  
    }  
}  
  
int main() {  
    int a, b;  
    if (scanf("%d%d", &a, &b));  
    if (b - a == 1) {  
        printf("1\n");  
        return 0;  
    }  
    for (int i = 0; i < 100; i++) {  
        for (int j = 0; j < 29; j++)  
            ans[i][j] = '0';  
        ans[i][29] = '\0';  
    }  
    ans[a][0] = ans[a + 1][0] = '1';  
    for (int i = a + 2; i <= b; i++)  
        sum(i);  
    int i = 28;  
    for (; i > 0; i--)  
        if (ans[b][i] != '0')  
            break;  
    for (; i > -1; i--)  
        putchar(ans[b][i]);  
    putchar('\n');  
    return 0;  
}  